Abstract
We investigated tree community structure and species diversity of naturally regenerated forests in 11 plots within four urban green areas in Nagoya, Japan. Although tree layers were always dominated by both deciduous and pine species, 50% of plots had evergreen-dominated sub-tree layers, suggesting a transition toward evergreen-dominated forests. Meitoku-koen showed the highest overall diversity and the greatest richness of both native and alien species. Total diversity was hierarchically and additively partitioned into three components: among green areas (β2), among plots within green areas (β1), and within plots. The observed β2 was significantly larger than the expected one and contributed 46% of total diversity, indicating that differences among green areas are important to overall biodiversity. The observed β1 was also significantly larger than the expected one, and included differences in topography and history of past forest use. To conserve the naturally regenerated forests of this region, it is important to avoid further losses of green areas by an urbanization and land development that can reduce habitat heterogeneity.
